Comment PR guidance

[glenn-jocher]

🛠️ PR Summary

_{Made with ❤️ by Ultralytics Actions}

🌟 Summary

Improvement of the PR template for better contribution clarity.

📊 Key Changes

• Introduction of a comment section at the start of the template.
• Removed unnecessary line breaks to streamline the template's appearance.

🎯 Purpose & Impact

• The comment section provides contributors with preliminary guidelines to ensure their contributions are unique and non-duplicative.
• Linking related issues directly connects PRs to existing conversations, improving project traceability.
• Encouraging elaboration ensures contributors share enough information about their changes for easier review and integration.
• The streamlined look minimizes clutter, which helps focus attention on the content of the guidelines.

Overall, these changes aim to make the process of contributing more straightforward and efficient, helping maintain the high quality of the Ultralytics project. The contributors are now better guided to provide meaningful PRs, enhancing the project's development and user experience. 🚀💡